package com.laipai.app.common;

import java.io.UnsupportedEncodingException;

public class URLEncoder {
	private URLEncoder() {
	}

	private static final String[] hex = { "%00", "%01", "%02", "%03", "%04", "%05", "%06", "%07", "%08", "%09", "%0A", "%0B", "%0C", "%0D", "%0E", "%0F", "%10", "%11", "%12", "%13", "%14", "%15", "%16", "%17", "%18", "%19", "%1A", "%1B", "%1C", "%1D", "%1E", "%1F", "%20", "%21", "%22", "%23", "%24", "%25", "%26", "%27", "%28", "%29", "%2A", "%2B", "%2C", "%2D", "%2E", "%2F", "%30", "%31", "%32", "%33", "%34", "%35", "%36", "%37", "%38", "%39", "%3A", "%3B", "%3C", "%3D", "%3E", "%3F", "%40", "%41", "%42", "%43", "%44", "%45", "%46", "%47", "%48", "%49", "%4A", "%4B", "%4C", "%4D", "%4E",
			"%4F", "%50", "%51", "%52", "%53", "%54", "%55", "%56", "%57", "%58", "%59", "%5A", "%5B", "%5C", "%5D", "%5E", "%5F", "%60", "%61", "%62", "%63", "%64", "%65", "%66", "%67", "%68", "%69", "%6A", "%6B", "%6C", "%6D", "%6E", "%6F", "%70", "%71", "%72", "%73", "%74", "%75", "%76", "%77", "%78", "%79", "%7A", "%7B", "%7C", "%7D", "%7E", "%7F", "%80", "%81", "%82", "%83", "%84", "%85", "%86", "%87", "%88", "%89", "%8A", "%8B", "%8C", "%8D", "%8E", "%8F", "%90", "%91", "%92", "%93", "%94", "%95", "%96", "%97", "%98", "%99", "%9A", "%9B", "%9C", "%9D", "%9E", "%9F", "%A0", "%A1", "%A2",
			"%A3", "%A4", "%A5", "%A6", "%A7", "%A8", "%A9", "%AA", "%AB", "%AC", "%AD", "%AE", "%AF", "%B0", "%B1", "%B2", "%B3", "%B4", "%B5", "%B6", "%B7", "%B8", "%B9", "%BA", "%BB", "%BC", "%BD", "%BE", "%BF", "%C0", "%C1", "%C2", "%C3", "%C4", "%C5", "%C6", "%C7", "%C8", "%C9", "%CA", "%CB", "%CC", "%CD", "%CE", "%CF", "%D0", "%D1", "%D2", "%D3", "%D4", "%D5", "%D6", "%D7", "%D8", "%D9", "%DA", "%DB", "%DC", "%DD", "%DE", "%DF", "%E0", "%E1", "%E2", "%E3", "%E4", "%E5", "%E6", "%E7", "%E8", "%E9", "%EA", "%EB", "%EC", "%ED", "%EE", "%EF", "%F0", "%F1", "%F2", "%F3", "%F4", "%F5", "%F6",
			"%F7", "%F8", "%F9", "%FA", "%FB", "%FC", "%FD", "%FE", "%FF" };

	/**
	 * Encode a string according to RFC 1738. <p/> <quote>
	 * "...Only alphanumerics [0-9a-zA-Z], the special characters "$-_.+!*'()," [not
	 * including the quotes - ed], and reserved characters used for their reserved purposes
	 * may be used unencoded within a URL."</quote>
	 * <p/>
	 * <ul> <li><p>The ASCII characters 'a' through 'z', 'A' through 'Z', and '0' through
	 * '9' remain the same.
	 * <p/>
	 * <li><p>The unreserved characters - _ . ! ~ * ' ( ) remain the same.
	 * <p/>
	 * <li><p>All other ASCII characters are converted into the 3-character string "%xy",
	 * where xy is the two-digit hexadecimal representation of the character code
	 * <p/>
	 * <li><p>All non-ASCII characters are encoded in two steps: first to a sequence of 2 or
	 * 3 bytes, using the UTF-8 algorithm; secondly each of these bytes is encoded as "%xx".
	 * </ul>
	 *
	 * @param s The string to be encoded
	 * @return The encoded string
	 */
	public static String encodeUTF8(final String s) {
		final StringBuffer sbuf = new StringBuffer();
		final char[] sChars = s.toCharArray();
		final int len = sChars.length;
		for (int i = 0; i < len; i++) {
			final int ch = sChars[i];
			if ('A' <= ch && ch <= 'Z') { // 'A'..'Z'
				sbuf.append((char) ch);
			} else if ('a' <= ch && ch <= 'z') { // 'a'..'z'
				sbuf.append((char) ch);
			} else if ('0' <= ch && ch <= '9') { // '0'..'9'
				sbuf.append((char) ch);
			} else if (ch == '-' || ch == '_' // unreserved
					|| ch == '.' || ch == '!' || ch == '~' || ch == '*' || ch == '\'' || ch == '(' || ch == ')') {
				sbuf.append((char) ch);
			} else if (ch <= 0x007f) { // other ASCII
				sbuf.append(hex[ch]);
			} else if (ch <= 0x07FF) { // non-ASCII <= 0x7FF
				sbuf.append(hex[0xc0 | (ch >> 6)]);
				sbuf.append(hex[0x80 | (ch & 0x3F)]);
			} else { // 0x7FF < ch <= 0xFFFF
				sbuf.append(hex[0xe0 | (ch >> 12)]);
				sbuf.append(hex[0x80 | ((ch >> 6) & 0x3F)]);
				sbuf.append(hex[0x80 | (ch & 0x3F)]);
			}
		}
		return sbuf.toString();
	}

	private static String encodeBytes(final byte[] s) {
		final StringBuffer sbuf = new StringBuffer();
		final int len = s.length;
		for (int i = 0; i < len; i++) {
			final int ch = (s[i] & 0xff);
			if ('A' <= ch && ch <= 'Z') { // 'A'..'Z'
				sbuf.append((char) ch);
			} else if ('a' <= ch && ch <= 'z') { // 'a'..'z'
				sbuf.append((char) ch);
			} else if ('0' <= ch && ch <= '9') { // '0'..'9'
				sbuf.append((char) ch);
			} else if (ch == '-' || ch == '_' // unreserved
					|| ch == '.' || ch == '!' || ch == '~' || ch == '*' || ch == '\'' || ch == '(' || ch == ')') {
				sbuf.append((char) ch);
			} else { // other ASCII
				sbuf.append(hex[ch]);
			}
		}
		return sbuf.toString();
	}

	public static String encode(final String s, final String encoding) throws UnsupportedEncodingException {
		if ("utf-8".equalsIgnoreCase(encoding)) {
			return encodeUTF8(s);
		}

		return encodeBytes(s.getBytes(encoding));
	}

}